24.17 Solubility Demonstration -- Extraction

Chemical ConceptDemonstrated: The tendency for
ionic substrates to extract into more polar solvents

Demonstration:

75 mL of water are poured into a funnel.

A blue ether solution, made up of KSCN,
CoCl2, and ethyl ether, is added to the funnel.

The funnel is stoppered and the contents inside are shaken.

Observations:

The water layer changes into a pink solution at the bottom of the
separatory funnel.

Explanation:

Water is more polar than ethyl ether. Some of the Co2+
ions are extracted into the water layer from the Co(SCN)42- complex
ions formed in the ether solution. The presence of Cl - can be seen by
adding silver nitrate (AgNO3) solution until a white precipitate forms in the
water layer at the bottom of the separatory funnel.